The present invention relates to a power rectifier module and, more particularly, to a power rectifier module which draws power from the line at unity power factor and which contains only four user accessible terminals.
Bridge rectifiers are used extensively for converting AC line voltage to smooth DC power for all kinds of electrical and electronic devices Typical applications include switching power supplies, motor controls, etc.
Conventional bridge rectifiers have DC smoothing capacitors and draw a non-sinusoidal current from the power line which is rich in harmonics, i.e., sharp edged current pulses These current pulses of conventional bridge rectifiers have a tendency to "contaminate" the power line and, as a result, increasingly more stringent regulations are being enacted throughout the world which impose restrictions on rectification of the line voltage
In response, the prior art has evolved methods for drawing current from the line in a manner which eliminates or ameliorates the problem Essentially, the method is based on controlling the manner in which current is drawn so that power is drawn from the line at or near a unity power factor. Examples of the prior art's solution to this problem are described in a pair of application notes from Siemens, including a first application note entitled "ACTIVE HARMONIC FILTERING FOR LINE RECTIFIERS OF HIGHER OUTPUT POWER" published in SIEMENS COMPONENTS, January, 1986, pp. 9-13 and in a second application note entitled "TDA 4814-INTEGRATED CIRCUIT FOR SINUSOIDAL LINE CURRENT CONSUMPTION" originally published in SIEMENS COMPONENT, March, 1986, pp. 103-107.
The solution of the prior art requires a user to assemble his own "electronic rectifier", using discrete components, including a bridge rectifier, a MOSFET, a series diode, and a control chip. Of course, all of these components can be packaged in a single module. But this would require six power terminals including: two input terminals, two output terminals, and another two terminals to loop the standard external inductor and capacitors into the circuit.